Users of Google’s Android mobile phone operating systems and some Google apps on iPhones are having their location data tracked and recorded, even if users opt out of being tracked, an investigation from the Associated Press found Monday.

Google offers users a setting called “Location History” that records a Google user’s location over time on a geographic map. The opt-in feature can be “paused,” which Google says makes it so “the places you go are no longer stored.” But as the AP demonstrated, the feature doesn’t actually turn off location tracking.

“Even with Location History paused, some Google apps automatically store time-stamped location data without asking,” the AP reported, adding that the disclosures that Google displays on mobile phones when users turn off Location History are “difficult to interpret” and “misleading.”

Princeton University postdoctoral privacy researcher Gunes Acar demonstrated through an Android phone he carried that Google tracked and recorded the locations where Acar traveled over the course of several days, even though he had disabled Google’s Location Services. The AP published a map of the data, which can be viewed here.

The AP pointed to several other instances in which Google tracked users’ location data even when users opted out. Around 2 billion Android operating system users and hundreds of millions of iPhone users who use Google Maps or Google Search could be affected, according to the AP.

The user location data Google stores is scattered throughout a number of different settings, so turning off Location History doesn’t disable Google from collecting other forms of detailed location data about users. As the AP reported, Google’s storage of location markers under the site’s “Web and App activity” setting is automatically enabled.

In a statement to Adweek, a Google spokesperson defended the company’s privacy practices, saying its data collection policies are clear.

“Location History is a Google product that is entirely opt-in, and users have the controls to edit, delete or turn it off at any time,” the spokesperson said. “As the story notes, we make sure Location History users know that when they disable the product, we continue to use location to improve the Google experience when they do things like perform a Google search or use Google for driving directions.”

Google uses location data to provide to its users with services like navigation guidance, nearby businesses and local weather forecasts. Google stores that location data before selling it in an anonymized form to advertisers. Those advertisers can use the information to better target customers based on where they are and what places they frequent, as well as measure the effectiveness of certain advertising campaigns, according to Google.

But privacy experts have repeatedly raised concerns about the security risks of detailed location data that often reveals personal information like home addresses and frequented locations. While Google anonymizes location data before selling it to advertisers, the company may be compelled by a court order to provide detailed datasets for investigations.

This isn’t the first time Google has faced scrutiny for the way it collects location data. In 2017, an investigation by the website Quartz revealed that Google was tracking Android users’ location using cell tower data, even if location services on the devices were disabled.

In May, Sens. Edward Markey, D-Mass., and Richard Blumenthal, D-Conn., said they were pushing the Federal Trade Commission to investigate Google over its data-collection practices, particularly its location data collection. In an email to Adweek, a spokeswoman for the FTC said that the organization cannot comment on whether they are or are not looking into specific companies.